A bit of finely grated semisweet chocolate for garnish
Add all of the ingredients to a standing blender, beginning with the coffee.
Blend on high until everything is incorporated and the drink is a relatively smooth consistency.
Serve! (Use a fine grater to grate a bit of chocolate on top of each serving.)
You can make a pitcher of this drink ahead of time if you're expecting more than a few guests. If you do so, make sure to stir it a bit before serving each glass. (It's the most delicious if you're able to make it "to order.")